104 ALTERNATING GENERATORS AND SYNCHRONOUS MOTORS. 
Tr 
On referring to the magnetic circuit, Fig. 42, in connection 
with the dimensions given in Figs. 59 and 60, we have: 
a= 5.6 inches; r= 1.33 inches; 1 = 5.5 inches; 0 = 2.08 
inches; 6 = 0.2 inches; u— 0.2 inches; s = 0.75 inches; 
¢ = 0.63 inches; f — 5.4 inches; n = 2.7 inches; d = 7.37 
inches ; m = 4 inches; and b = 3.95 inches. 
Hence the air gap reluctance from Formula (20) will be 
ee 0,313 0.813 26, 
°"5.6X1.33X5 5, 5.55 6X(0.2+0.38) 9821.5 10% 
2.08X0.2  ° 2.08 X 0.4 
and from Formula (23), a value for the reluctance of 
the field leakage path of: 
xe 0.313 0618 7 
1 4X 0,635.4 ,4X7.37X5.4 43 95X7.387 54+40414 10° 
et Ste 4 Se 7.9 
is found. 
Consequently, in accordance with Formula (26), a leakage 
factor 6 of 1.49 is obtained. : 
If the two other items of Formula (25) are taken into con- 
sideration, a further 6 per cent of 0.49 must be added to o, 
thus making 6 = 1.52. 
Assuming an average constant value for the above degrees 
of saturation, it follows that the field system will carry 
a flux of 
2.37 X 10° lines for an E.M.F. of 3,500 volts, 
2.04 x 10° lines for an E.M.F. of 3,000 volts, 
1.70 x 10° lines for an E. M. F. of 2,500 volts, and 
1.36 x 10° lines for an E.M.F. of 2,000 volts. 
Fietp Ampere Turns: By means of Formula (34), the 
necessary number of field ampere turns may be calculated, 
by fixing the values of the length of the different paths and 
by taking from the magnetizing curves of Fig. 46, the 
values of the ampere turns per unit length of the various 
paths. 
——— = 
